random-access

According to the PDF 1.7 specification, Sec 3.4 ( http://www.adobe.com/content/dam/Adobe/en/devnet/acrobat/pdfs/pdf_reference_1-7.pdf , page 90): The preceding sections describe the syntax of individual objects. This section describes how objects are organized in a PDF file for efficient random access and incremental update. A canonical PDF file initially consists of four elements (see Figure 3.2): A one-line header identifying the version of the PDF specification to which the file conforms A body containing the objects that make up the document contained in the file A cross-reference table

I'd like to be able to do random access into a gzipped file. I can afford to do some preprocessing on it (say, build some kind of index), provided that the result of the preprocessing is much smaller than the file itself. Any advice? My thoughts were: Hack on an existing gzip implementation and serialize its decompressor state every, say, 1 megabyte of compressed data. Then to do random access, deserialize the decompressor state and read from the megabyte boundary. This seems hard, especially since I'm working with Java and I couldn't find a pure-java gzip implementation :( Re-compress the

What is the best compression algorithm that allows random reads/writes in a file? I know that any adaptive compression algorithms would be out of the question. And I know huffman encoding would be out of the question. Does anyone have a better compression algorithm that would allow random reads/writes? I think you could use any compression algorithm if you write it in blocks, but ideally I would not like to have to decompress a whole block at a time. But if you have suggestions on an easy way to do this and how to know the block boundaries, please let me know. If this is part of your solution,

I've read that accessing elements by position index can be done in constant time in a STL deque. As far as I know, elements in a deque may be stored in several non-contiguous locations, eliminating safe access through pointer arithmetic. For example: abc->defghi->jkl->mnop The elements of the deque above consists of a single character. The set of characters in one group indicate it is allocated in contiguous memory (e.g. abc is in a single block of memory, defhi is located in another block of memory, etc.). Can anyone explain how accessing by position index can be done in constant time,

I've got a text file that contains several 'records' inside of it. Each record contains a name and a collection of numbers as data. I'm trying to build a class that will read through the file, present only the names of all the records, and then allow the user to select which record data he/she wants. The first time I go through the file, I only read header names, but I can keep track of the 'position' in the file where the header is. I need random access to the text file to seek to the beginning of each record after a user asks for it. I have to do it this way because the file is too large to